The present invention relates to a dual-band inverted-F antenna. More particularly, it relates to an inverted-F printed antenna that can be operated in two separate bands.
To follow the advancement of the communication technology, the applications using communication technologies have been increased significantly and the related products have become more diversified. Especially, consumers have more demands for the functions of communication applications, so that there are many communication applications with different designs and functions issued continuously. For example, the products with one-piece design of dual-band or triple-band, and even the implementations of multi-band operation using one single antenna are the main streams. Moreover, by utilizing IC technologies, the size of products will become smaller in future.
Microstrip antennas or printed antennas are becoming more attractive, because they are very suitable for applications in present-day communication products. Among various types of designs, the inverted-F antenna has the attractive features of small volume, simple structure, easy design, etc., and the inverted-F antenna has been utilized popularly in various products and communication systems in recent years, especially in the products required for easy, convenient, and good receiving/transmitting capabilities.
However, a conventional inverted-F antenna only has a function of single operating frequency. If the conventional inverted-F antenna is utilized in dual-band products or multi-band products, two or more inverted-F antennas are required for the multi-band operation. Therefore, the difficulty in the design of products increases, and the size and cost of products increase accordingly.
In the view of the background of the invention described above, an antenna is an important part in wireless communications, since the performance of wireless communications is greatly affected by the antenna. Therefore, low cost, high efficiency and simple implementation are the major trends for the design of antenna. The conventional inverted-F antenna has several features, such as small volume, simple structure, easy design, etc., so that the conventional inverted-F antenna has been used widely. However, the conventional inverted-F antenna has the disadvantage that it can be operated in a single band only.
It is the principal object of the present invention to provide a dual-band inverted-F antenna. More particularly, the present invention relates to an inverted-F printed antenna that can be operated in two separate bands. More complete functions and wider operating frequency range are attained and provided, because the dual-band inverted-F antenna of the present invention can be operated both in a low frequency band and in a high frequency band. Moreover, the implementation of the present invention is valuable in industrial field, because the dual-band inverted-F antenna of the present invention can be operated in two separate bands, and can be printed on a microwave substrate, which makes it easy to integrate with other associated microwave circuitry.
In accordance with the aforementioned purpose of the present invention, the present invention provides a dual-band inverted-F antenna. The main radiating component of the dual-band inverted-F antenna of the present invention is two stacked radiating metal lines that are fed and driven by a same feeding line. According to the different lengths, widths and shapes of the two stacked radiating metal lines, the dual-band inverted-F antenna of the present invention can be operated in a low frequency band and a high frequency band, and their frequency ratio can also be adjusted easily. Moreover, since the radiating metal lines and the ground plane are printed directly on a substrate, the cost is thus lower and the manufacturing can be processed easily.